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How do you solve the equation all four equations are 1 problem. i have to solve for w, x, y and z

x + y + z - w= 4

2x + y - z + w =3

x - 5y + 2z +w = -4
-x -y + z + 3w = 2

Asked by Anonymous at 11:33 PM on Sep. 13, 2010 in

• Ecodani is right on. Another method to use is linear algebra by building a matrix.

Write your equations this way, and solve for the diagonal (underlined).
1   1   1  -1   4
2   1  -1   1   3
1  -5   2   1  -4
-1 -1   1   3   2

Add/subtract rows from each other till the only values >0 left are those on the diagonal (x,y,z,w) and last column (value).

My solution: x=-7, y=14, z=21 2/3 and w=24 2/3

Answer by anng.atlanta at 12:58 AM on Sep. 14, 2010

• First solve for x. Plug that equation in for x in the following equation. Then solve that equation for y. Plug the x and y in the 3rd equation andnsolve for w. Finally, you only have z as your variable. Solve for z.

Answer by ecodani at 11:48 PM on Sep. 13, 2010

• i swear i should know that because it was only 2 semesters ago that i was doing that problem.. sorry =( i'll try to figure it out & get back to you IF i remember! =P

Answer by rAbella at 11:47 PM on Sep. 13, 2010

• I SHOULD know this, lol, Good Luck! I'm drawing a blank!

Answer by sstepph at 7:00 AM on Sep. 14, 2010

• best way to make sure you are getting help is to visit the professer and ask them. Many will help during office hours and others know of the best tutors available many times for free.

Answer by steveiguana at 7:23 AM on Sep. 14, 2010

• I am no help, sorry. I can barely help my fifth grader with his math. :(

Answer by KTMOM at 8:34 AM on Sep. 14, 2010

• OMG, so sorry-I never understood that kind of math!

Answer by NicolesMommy at 12:14 AM on Sep. 15, 2010

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